The faithful of Borough Park have a saying: “We are all of one face.” The life of Levi Aron, the outcast awaiting trial for the murder of 8-year-old Leiby Kletzky, suggests otherwise.

Late in the evening of July 11, Yaakov German, a 47-year-old Bobover Hasid, received a call from his brother, Benny. “Yanky,” Benny said, “a boy is lost in the community. You’ve got to come help.” German, who is short and thickly built, sprang from his chair and headed out into the heat.

Borough Park was already thrumming with somber activity. Men in black coats and black hats waded through backyards and back alleys, flashlights in hand. On adjoining balconies, women in trim dark dresses worked their phones, prodding friends and family for information. The bookstores and kosher restaurants filled with concerned citizens. In the cavernous shuls on Thirteenth Avenue, the high street of the Jewish settlement, rabbis urged prayers for the missing child. Borough Park, which sits between Flatbush and Bensonhurst in southwest Brooklyn, is by some estimates the most densely Orthodox neighborhood outside of Israel, and residents are accustomed to looking after their own. “We are all of one face,” goes a popular saying. “We are like tea bags,” goes another. “When it gets hot, we stick together.” The first call placed by ­Esther Kletzky, the mother of the missing child, had been to the Borough Park Shomrim, a Hasidic anti-crime patrol.

It was the offices of the Shomrim—­Hebrew for “watchers”—that German ­initially visited. From the search coordinators he learned the basics: The boy, an 8-year-old named Leiby, was short and slight, with dark peyos, or side curls. He had disappeared on his way home from day camp at Yeshiva Boyan, a large neighborhood Jewish school. It was Leiby’s first time making the trip alone, but that his parents had allowed him to do so was not unusual. In Borough Park, crime rates are low, residents are trusting, families are large (Leiby was one of six kids), and children earn their independence at a very young age, the better to help their overworked mothers watch their even younger siblings. Moreover, Leiby’s intended route was simple and short: one block southeast from the yeshiva, on 44th Street, before turning right, onto Thirteenth Avenue, where he would meet his mother. His parents had practiced with him.

German, a father of twelve, is well known in Borough Park both for his real-estate holdings and his indelicate demeanor. He had himself been involved with the Shomrim as a younger man, but he chafed at the patrol’s protocols and came to conclude that his energies would be better deployed on a freelance basis. By his own count, he has tracked down “a lot of criminals.” In 2003, when a neighborhood house went up in flames, he famously barreled past a wall of angry firefighters and carried the waiting children to safety. (“My wife worries,” he says. “But I know that when my time comes, it comes.”) Now German was about to clash with the Shomrim again. The search coordinators, German remembers, were casting a wide net. To him this made little sense. “I tried to think logically. Like a detective,” he says. “I thought, Well, we have to go to the last point he was seen alive.” But the Shomrim were unyielding. After a few minutes, German threw up his arms. “I knew I’d have to do it myself.”

He made it to Yeshiva Boyan around 11:30 p.m. With the help of his son Avrumy, who worked as an instructor there, German accessed the footage from a camera facing 44th Street. For two hours, his eyes reddening with the effort, he pored over footage of teeming masses of boys in yarmulkes. Then, finally, he spotted Leiby, carrying a backpack and holding a satchel in one hand. German formulated a plan: In the morning he would work his way down 44th Street and demand that its business owners turn over their security tapes, so that he could look for that satchel and piece together where the boy had gone. Back at home, German spent a sleepless night pacing the floor of his basement, reading aloud from the Torah to calm his nerves.

After setting out the next morning, German called Leiby’s father, Nachman, to report his progress. “I’m going to find him,” he promised.

German had heard the speculation—Leiby had been snatched by an outsider, perhaps a Hispanic or black man from one of the adjoining neighborhoods. But he did not despair. Years earlier, he had been involved in the hunt for Suri Feldman, a young girl who had vanished on a field trip to a Connecticut park. Then, too, some searchers feared that the child had been abducted and killed, probably by a non-Jew. They were looking for a corpse. German had been among the men who found the girl, alive and shaken, praying under the boughs of a tree. “Have faith,” he told himself.